Glyptemys insculpta, or the Wood Turtle, is a relatively small turtle that gets its name from its distinct shell or carpace. Unlike other turtle species which shed the scutes – the exosceletal scales that cover its shell – annually, the Wood Turtles scutes remain attached to the new growth and form pyramidal scales resembling a collection of wood rings. The new scales grow in slightly larger than the previous year’s growth, forming an ever-expanding series of rings by which the age of the turtle can be determined.
The scutes are actually fused bones that make up the spine and ribs of the animals and are identified by the same patterns found in vertebrates: vertebral scutes cover the center spine region, costal scutes cover the ribs, marginal scutes form the outer margin of the shell and a single nuchal scute is situated at the nape of the neck. The shell material is actually keratin, similar to the hard protein that forms nails in mammals.
Wood turtles inhabit fresh water regions that offer a wide selection of food sources for these omnivorous reptiles. Worms, snails, slugs, and leeches are abundant food sources in their native habitat, which ranges from northeastern Canada to the northernmost regions of the northern United States. They prefer to dine on a protein-rich diet that is rounded out with small frogs, tadpoles, insects and larvae, immature mice, small fish and are even known to scavenge bird remains.
Ground nesting birds often lose their clutches of eggs to a hungry wood turtle that will take advantage of any easy food source. Wild mushrooms comprise as much as 37% of an adult Wood Turtles diet and the northern climes of their range offers an abundant variety of mushrooms for them to choose from. Their vegetal diet is rounded out with berries, grasses, algae, and leaves of alder, willow and birch trees, and a prolific collection of edible flowers such as wild violets, cinquefoil and dandelions.
The species is listed as endangered in Iowa, and is a watched species in Minnesota, Wisconsin and Michigan. However, it is considered threatened in every locale in which it is found and has come under heightened conservation scrutiny in recent decades. Wood turtles are extremely adaptable in their limited environment, a fact that scientists attribute to a high degree of intelligence. They are excellent climbers and in captivity are compared to rats in their ability to maneuver through mazes to find food or an escape route.
Vermin such as skunks, raccoons, opossums and chipmunks as well as coyotes, dogs, cats and many birds are noted for their predation upon the nests of the Wood Turtle. Ravenous fly colonies will infiltrate an unprotected nest to consume infertile eggs and have been known to severely injure hatchlings devoid of the bony protection afforded the adult by its solid carpace. Small groups of conservationists have made it their challenge to document the trends of this species and actively lobby for protective legislation to prevent its extinction. Through their tireless efforts the species may be preserved, to the wonder and delight of future generations.